Hello. First, let me apologize if this has been covered---I tried to search the mailing list archives but was unable to get that to work (even queries that should have returned many hits were returning nothing).
When I plot with the MacOSX backend using a serif font, the negative signs on the axis labels show up as the "missing glyph" open squares rather than minus signs.
Things that work around the problem:
- disabling the unicode minus sign via axes.unicode_minus: False in the matplotlibrc file (though this obviously gives a hyphen instead of a true minus sign)
- switching to a sans-serif font
- switching to TkAgg or wxAgg backends
- using the text.usetex option
Things that don't work:
- switching to a different serif font (at least among Times, Times New Roman, and Bitstream Vera Serif)
I am using matplotlib 1.0 installed from the dmg file for Python 2.6 on OSX 10.6. I'm using Python 2.6.6 installed from the python.org binary distribution.
For now, I can work around using a sans-serif font or different backend instead, but I'd really like to use a serif font with the MacOSX backend. Please let me know if you need any other information. Your assistance would be most appreciated, thank you.